Control apparatus for internal



June l2, 1951 H. T. SPARROW ETAL 25565986 CONTROL APPARATUS RoRINTERNAL-COMBUSTION ENGINES Filed oct. 17, 1947 (Iftorneg Patented June12, M1951 UNITED STATES PATENT OFFICE CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES Application October 17, 1947, Serial N0. 780,596

17 Claims. i

` This invention relates generally to improvements in intake manifoldpressure control systems for engines having combustion chambers that maybe of the internal combustion type, and more particularly toimprovements in control systems of this nature for use in connectionwith antidetonant injection for such engines.

As is well known in the art, it is the present custom, particularly inthe case of aircraft engines, to provide a means for compressing air anddelivering it to the intake manifold whereby manifold pressures muchgreater than atmospheric pressures may be obtained and the power outputof the engine greatly increased. For this purpose, there is provided aso-called turbosupercharger, consisting of an air compressor :and a gasturbine for operating the same. The controlling of this turbine isaccomplished by an electrical control system which positions a valve inthe exhaust system of the engine according to the input pressureselected by a controller in the network. A pressure sensitive devicemaintains the selected pressure, regardless of the varying pressures ofthe intake of the compressor, as when, in the case of an aircraftinstallation, the aircraft flies at varying altitudes.

It is well known in engine control art, that engine output may begreatly increased by injecting an atomized antidetonant such as waterinto the fuel intake system of the engine. Injection of thisantidetonant into the combustion fuel mixture has the eiiect ofpreventing overheating and detonation, permitting the operation of theengine at higher intake manifold pressures than would otherwise bepossible.

It is to be understood that while our inven-v tion is concerned with anyantidetonant injection apparatus, it will hereinafter be referred to asa water injection apparatus as that is the term generally used by thoseskilled in the art in discussing such an apparatus.

The present invention is concerned with that type of water injectionapparatus where water injection is had on a high range of pressuresselected by the main controller and not had on. the low range ofpressures selected. All the pres.- sures may be variably adjusted by thecontrol means whether there is water injection or not, barring failureof portions of the equipment.

In present day craft of larger size, it is customary to have the mainengine controls on the flight engineers deck with only auxiliarycontrols at the pilots control panel. In such instal'- lations, it isnecessary to provide means for the pilot taking over control of thepower control of the engine and have a maximum power output should someemergency arrive. Also, in present day craft, where much flying is doneat high altitudes, it is necessary to provide means for deicing of thecarburetor. This is sometimes acy complished by retarding the throttleand increasing the input pressure in the carburetor on the theory thatthe heat of the compression will melt any of the ice present. When usinga system employing water injection, as is done in the present invention,it is necessary to provide means for shutting down the water injectionwhen the control selector is moved into the advanced range of inputpressures to further aid the deicing operation. To protect the engine inthe event that the throttle is suddenly advanced, an auxiliary controlnetwork is provided and is switched into the circuit to set a maximumdry power signal in the control system.

In the event that the pilot needed maximum power output with waterinjection it would be necessary to provide switching means to by-passthe switching control of the flight engineer and energize a water valveand inject water into the system regardless of the settings of the ightengineers controls. Operating in connection with a water control valveis a water responsive device which in the absence of its detecting theproper amount of water iiowing into the engine will switch the controlsystem over to the auxiliary control network which will establish` themaximum dry power pressure for the engine.

It is therefore an object of the present invention to provide a controlapparatus which provides auxiliary means for switching to a maximumpower output pressure with water injection, and providing with thisfeature a safety cutout for going to an auxiliary control network shouldthe water injection apparatus fail to operate.

A further object of the present invention is to provide in a waterinjection control apparatus means for deicng the carburetor of theengine by running up carburetor pressures to a high value without waterinjection, and to provide means for switching to a maximum safe drypower in the event the throttle is advanced beyond a certain position.

.Another object of the present invention is to provide a water injectionsystem wherein the control selector may be advanced through one range ofdry values without water injection, and a further range of values withwater injection, with means to switch to maximum wet water injectionelements and controls therefor,V

arranged in accordance with theY present invention.

Referring now more particularly to the ing, there is shown an internalcombustion engine l which is receiving its air for combustion through anintake Compressing or" the air is accomplished by compressor I2 which inturn forces the air through conduit I3, inter-` cooler l4, conduit I5,carburetor I6, and conduit I1 to a further direct driven compressor I8.Driving compressor I8 is a shaft I9 directly connected to the engine.Conduit 2i) and intake manifold 2| form the output for the compressor |8and the intake for the engine I. The exhaust gases from the engine I0flowing through the conduit 22 and 23 act to drive turbine 24 which hasan output conduit 25. A drive shaft 26 connects the turbine 24 to thecompressor I2. Controlling the amount of exhaust gases nowing throughconduit 21 is a damper or valve 28, known as a waste gate. Connected tothe engine I0 is a propeller hub 23 with propellers 30 extendingtherefrom.

aoaese Positioning of the waste gate 23 is accom- Y plished by means ofa motor 3| Vwhich has a pair of exciting windings 32 and 33 which arespaced electrically 90 apart in order to make possible the inducing of areversible function into the motor. Energization for the winding 33 isfrom the transformer 31 which consists of a primary 35 connected to apower source not shown, and two secondary windings'38 and 39.

The winding, 38 directly energizes the winding` 33 through a condenser34. The other secondary winding 39 of transformer 31 is connectedrtoinput terminals 43 and 44 of an amplifier 43. Winding 32 of the motor 3|is energized by amplifier through the terminals 45 and 46 and accordingto the signal on the input terminals 4I and 42 of the amplifier 40.

The input signal for the amplifier 4!) comes from a complex electricalnetwork which consists of a manual control network 55, a pressurecontrol network 60 and a rebalancing network 15. This electrical networkcooperates with the amplifier 40 in a manner to be described hereinafterin a way to cause the motor 3| to rotate in one direction or the otherdepending upon the conditions in the electrical network.

The manual control network consists of a transformer 5| having a primary52 connected to a power source not shown, and a secondary 53. A slidewire resistor 54 and associated .wiper 55 act as the main manualcontroller while a potentiometer 55 and a potentiometer 51 act in acalibrating capacity, for the maximum wet position and the normaoperating range respectively of positions of the main controller.

The pressure responsive network 50 consists of a transformer 6| having aprimary winding 62 connected to a power source, not shown, and asecondary winding S3 which acts to furnish the controlling voltages fora slide wire resistor 64 andV its associated wiper 65 controlled by apair of pressure responsive bellows 66a and b. The duct 61interconnecting the conduit I5 of the engine and the bellows 66a acts totransmit the pressure from the input of the engine to the bellows 66a.The bellows 631) is an evacuated bellows which is bucking bellows 66aand compensating for changes in atmospheric pressure so that thepressure responsive device will indicate the absolute pressure in theconduit I5. Also energized by secondary winding 63 is a furtherpotentiometer 63 with its associated wiper 69. The wiper 69 is normallybiased to the right hand end of the resistor 68 so that it has novfunction in the control network until such time as the rotationalvelocity of the turbine 24 and compressor I2 exceeds a safe value. Whenthis occursa turbine overspeed governor 10 comes into operation andacting through a suitable linkage 1I moves the slider 69 to the left byan amount that will be proportional to the magnitude-of overspeed of theturbine 24.

includes a transformer 16 having a primary wind-A ing 11 connected to apower source, not shown, and a secondary winding 18. Associated withthis secondary winding 18 is a rebalancing potentiometer with itsassociated wiper 8| which is positioned by the waste gate motor 3 I. Afurther resistor 19 is associated with network 15.

An auxiliary control network 85, which under certain conditions is themain control in the electrical network in a manner to be describedhereinafter, consists of a transformer 86 having a primary winding 31connected to a power source, not shown, and a secondary winding 88. Thesecondary winding 88 energizes a slide wire resistor 89 and itsassociated wiper Si), the latter of which is directly coupled to thewiper of 'calibration potentiometer 51 by a couplng 9|.

All of the primary windings of the electrical of the electricalpotentials developed in the net.

works 5!) or 85, 60 and 15.

h Associated with this electrical network are a large number of switcheswhich are used to accomplish the controlling functions of the presentinvention. A pilot emergency switch consists of switch arms 96, 91 andand associated with the switch arms are contacts 99,V I, |0I, |02, |33,and |54. The arms 96, 91 and 98 are mechanically connected together soas to move together. A battery |56 supplies energy to relays associatedwith some of-the switching functions of the apparatus. A furtherswitching arrangement is provided by the throttle mechanism I0. Here,the throttle lever carries a contact I l2 which engages a contactsurface I3 when the throttle has been advanced to a set position. Astill further switching function is accomplished by the -slider 55 ofthe manual control network 55 in that when the slider is in one range ofvalues an electrical circuit will be completed through a wiper I I4 andcontact surface I5 and while the slider is in a further range of valuesan Y shown on the drawing in which it is in engage- Y ment with contact|2| and is movable upon enerannesse sgaton kof Coil H9 into engagementwith contact |20. A carburetor heat switch |25 consists QI a pair ofarms |26 and |21 and their assoelated contacts |728 and |29. Arms |26and r|211 are mechanically interconnected so as to be movable in unisonThe actuation of the water controlling function of the present inventionis accomplished by a relay |30 which consists of la relay winding |31,armature |32, switch arm |33 biased open by means not shown, and anassociated contact |34. A propeller feathering switch which consists of`Switch arm |36 and Contact |31 acts as a safety feature in a manner tobe described later. The water tank assembly |45 consists or" a storagetank for the water supply and suitable pumping means to maintain waterpressure in the system. A suitable electric water valve |5| is providedhaving input terminals |52 and |43. A duct |44 and nozzle y|45 act topass water into the intake system of the engine from the water tankassembly |40. A pressure responsive relay |50 is actuated when apressure responsive bellows |45 moves into engagement a pair of switchcontacts |41 and |48. The pressure responsive bellows |45 is locatedwithin a sealed housing |49 which is connected by duct Mea to thecarburetor outlet pressure. This housing establishes a substantiallyconstant pressure reference point for lille bellows |46. The relay |50consists of a winding |5|, armature |52, switch arm |53 biased open bymeans, not shown, into engagement with contact |54, and contact |55. Afurther element in the control network is the isolating resistor |56.

In discussing the operation of the basic regulator apparatus, it will beassumed that during one particular half cycle of the power supply thepolarities of the transformer secondaries will be as shown on thedrawing. In examining the network 50, it may be seen that with theslider 55 in the mid position of the resistor 54, and the calibrationpotentiometer in the position shown that there will be a potential whichwhen measuredv between the ground conductor 53 and the conductor 59 willbe positive by a certain amount. Movement of the slider 55 to the leftwill increase this signal and make it more positive while movement tothe. right will make the output signal less positive. Assume, forexample, that the voltage between the ground conductor 58 and conductor59 is a plus 6 volts.

Examination of network 55 shows that the polarity of the secondarywinding 53 is reversed to that of winding 53, so that movement of slider65 along resistor. 54 to the right produces a voltage that is lessnegative and movement to the left givesa voltage that is more negative.In measuring the voltage across the network 5 5 it will be assumed thatthe slider is is in the position shown and therefore lthe potentiometer53 has no affect on the circuit. Here, the voltage will be, lor example,minus volts when measured between slider 65 and slider 59.

In` network 15,k it will be noted that the polarity of the. secondarywinding 1 3 is positive on the left hand terminal and negative on theright hand terminal.` With the winding tapped as shown, there will be aconstant positive voltage in the networkdue to the right half of thewinding 18 and aA variable tapped positive voltage in the left half ofthe winding 18 picked off by a slider 8| acting with resistor 80. Byassuming a constantV voltage of plus 6 volts in the right half` of thesecondary and a variable tapped voltage of plus 3 volts, the totalvoltage between the slider 69 and the slider 8| will be plus 9 volts.

Now taking the algebraic sum of the voltages of networks 50, 60, and 15,we have plus 6, minus 15, and plus 9 which totals 0 volts. Therefore,the voltage between the slider 8| and the ground conductor 58 will be 0or the voltage between the input terminals 4| and 42 of the amplier 40will be 0 since the ground conductor 58 is grounded through Contact |05and switch arm 95 of the switch and terminal 42 of the amplifier 4o isgrounded at 83. Slider 8| is directly connected to terminal 4| by.conductor 84. From this it can be seen that the network is balanced andthere will be 0 volts on the input of the amplier and therefore therewill be no output signal in the output winding 32 to cause any rotationof the motor 3|.

Should there be a change in pressure in the conduit |5 such that thebellows 66a moves slider 65 toward the left there will be an increase inthe negative voltage across the network 60. Assume that this sliderchanges the voltage on network 60 from a minus 15 to a minus 16 volts.As the networks 50, 6D and 15 are connected in series to the inputterminals of amplifier 40, this change in voltage will result in a minusl volt appearing on the input of the amplifier. The amplifier nowenergizes winding 32 and starts repositioning the waste gate 28 in apressure maintaining direction and will also move the follow up slider8| toward the left to remove the unbalance created by the movement ofslider 65. In other words slider 8| will add a plus l voltage in thecontrol network. With the movement of the waste gate there will be achange in the now of exhaust gases through turbine 24 so that its speedwill be modied. The change in speed will change the amount of aircompressed by compressor |2 and this will result in a change in pressurein conduit I5 and a change in the position of the pressure slider 65back to the desired position. As the pressure is restored to the desiredvalue the network will be unbalanced in the opposite direction whichunbalance will cause the waste gate 28 to be moved substantially back toits original position. Thus the unbalance voltage in the control networkoriginally due to a change in pressure will have been eliminated bymovement of the waste gate follow up slider 8| and the subsequentrepositioning of the pressure slider E5.

Movement of the manual control slider 55 will also result in anunbalance on the input terminals of amplier 4|). The waste gate motorwill accordingly reposition the waste gate 28 in aV direction tocorrespond to the signal introduced by movement of slider 55. Theunbalancc created will be balanced out by the subsequent movement of thepressure slider 55 and the follow up slider 8| as soon as the desiredpressure change has been brought about.

Should an overspeed condition occur at turbine l2, the overspeedcontroller lil will starty moving the slider 69 toward the left. Thismovementy will result in a less negative signal being introduced in thecontrol network by network 60. This4 less negative voltage will resultin the moving of waste gate '28 in an open direction so that there willbe less gases driving the turbine t2 and its speed will drop off to asafe value.

Operation with water injection In discussing the operation of theturboregulator above no mention was made of the action ofV the variousswitching arrangements associated with the present invention asconcernscontrol for water injection. In the design of this turboregulatorapparatus, it is desirable when moving the slider 55 of the manualcontrol network 50 from the far left position or the position toward theright that there be an increase in pressure at the intake to the engine.ItV is also desirable when moving the slider 55 toward the right thatthere be a range of dry values and a range of wet values, the formerbeing on the lower range of pressure values and the latter being on thetop range of pressure values. Therefore, in the design of such a slidera switching arrangement is provided on the slider which is responsive tothe position of the slider 55 on theV resistor 54 so that as soon as thehigh range of values has been reached a switching function will takeplace to actuate the water control mechanism injecting water into thesystem. This is ac-V complished by the switching mechanism on the end ofthe slider 55 and consists of the wiper ||4 acting with Contact surfacesi and. I! 6; When the slider is in the range from 0 to 5 on thel re'sistor 54 the wiper I I4 will be engaging the contact surface ||5 and assoon as the high Arange of positions has been reached the wiper ||4moves into engagement with contact surface |6. The last mentionedconnection is maintained as long as the slider is in the range ofVvalues of from 5 to 10 on the resistor 54. Control position responsiverelay ||8 will be deenergized, as shown, when the slider 55 is in thehigh range of positions (5 to l0). This is because Ythe relay I I8 isnormally energized by battery |06 through conductors |66 and |5I, switcharm 91, switchA contact |02, conductor |62,Yblade H4, contact |l5,conductor |81, relay winding ||9 to ground |88 and thus back to ground|95 of the battery |06. Obviously, when blade ||4 moves out oilengagement with contact ||5, the relay ||8 will be deenergized and arm|22 will engage contact |2|. Y Y

Assuming that the slider 55 is in the rangetof from 5 to 10 on resistor54 and that the blade wiper H4 is in engagement with surface ||6, it maybe seen that a circuit will be completed to the water injection controlrelay |30. Thisv circuitV may be traced from the positive terminal ofthe storage battery |66 through conductors |69 and |6|, switch arm 91,switch contact |92, conductor |62, wiper H4, contact surface H6,conductor |63, Contact |04, switch arm 93, conductor |64, conductor |55,switch Contact |29, switch arm |26, conductors |66 and |61, relaywinding |3|, ground connection |68 and thus to I ground connection |65of the battery |06. When water injection relay |30 becomes energized,the switch arm |33 moves into engagement Y with the switch contact |54,which action causes the water control valve |4| to be. energized. Thisenergizing circuit may be traced from the posi` tive terminal of thebattery |96 through conduc-v tor |60, conductor |69, switch contact |34,switch arm |33, conductorY |16, switch arm |36, switchA contact |31,conductors |1| and |12, termin'al |42, Valve |4|, terminal |43 to ground|13 and thus to ground connection |95 of battery |06.

With the energizing of the water control valve |4|, waterV will bepermitted to ilow through" the duct |44V to Ythe nozzle |45 where itwill be injected into the intake system of the engine. Also situated Vonthe duct |44 is a pressure responsive bellows |46 which acts to completetheA water responsive relay energizing circuit. This last namedenergizing circuit may be traced from 'ity 8. the positive termina1 ofthe batteryV |06 through conductor |60, |69, switch contact |34, switcharm |33, conductor |10, switch arm |36, switch contact |31, conductor|1|, conductor |14, relay winding |5|, conductor |15, switch contact|48, Vswitch contact |41, to ground connection |16, and thus to groundconnection |95 of battery |06. With the energization of relay |50, itwill be noted that the switch arm |53 moves out of engagement withcontact |54 and into engagement with contact |55 Yto effectively by-passthe isolating resistor |56. This by-passing circuit may be traced fromthe lower terminal of the isolating resistor |56 through conductor |11,switch arm |53, switch contact |55, and conductor |18 back to the upperterminal of the isolating resistor |56. It may now be seen that theturboregulator bridge is acting in its normal capacity for regulatingthe pressure at the intake of the system and as the slider 55 is movedbetween the positions 5 and 10 of the resistor 54 the position of theslider will change the pressure in the input accordingly. As long asthat slider is in this range there will be water injection barringfailure of the water supply system itself. In the event that thereshould be a watery failure, it will be noted that the pressureresponsive bellows |46 will retract and open contacts |41 and |48. Whenthese contacts, |41 and |48, are opened the relay |50 will bedeenergized and the switch arm |53 will move into engagement with theswitchcontact |54. When this occurs a new control network isswitchedinto the electrical network. This circuit may be traced from the slider65 of the pressure'responsive network 66 through the conductor |11,switch arm |53, contact |54, conductor |19, conductor |80, switchcontact |28, switch arm |21, conductor |8l, switch arm |22, switchContact |2|, and conductor |82, to the slider 99 of the electricalnetwork which is grounded at |83. This auxiliary control network is socalibrated by the potentiometer wiper 90, which is adjusted by movementof the wiper of calibration potential meter 51, that upon a failure ofthe water supply system the engine pressure will automatically bewitched to a maximum dry power position to prevent excess pressures frombuilding up in the engine without water being present.

The action of the isolating resistor |56 is to effectively isolate thecontrol network 50Vi`rom the electrical network when there is a directconnection to the auxiliary network 85, as explained above, when thewater responsive `switch |50 fails to indicate water. When theelectrical network 5i is functioning in its normal capacity, with thewater responsive relay |50 indicating the presence of water, theresistor |56 will be in the electrical network and will have no eect inthat network because there is no voltage induced across the resistoritself. It will be remembered thatV the input on terminals 4| and 42 ofthe amplier 46 is the result of the algebraic sum of the electricalnetworks 56, 60, and 15 and when there is no voltage induced across theresistor |56 it can be seen that there will be no effect on the controlpoint of the electrical network. However, when the apparatus hasswitched over to the auxiliary control network 85,V the two controlnetworks 85 and 50 would be acting against each other in the controlnetwork were it not for the isolating resistor |56 effectivelyeliminating the signal from the network 50. This resistor actually formsanV effective voltage divider which insofar as the signal from network85 is concerned consists of the resistance |56 and network 50 in serieswith all of the voltage of the network 85 appearing on slider 65. Whenthe signal from network 50 is considered, the voltage divider consistsof the resistor |56 and the network 85. Since the rest of the controlnetwork couples to the voltage divider at the junction of the resistor|56` to network 85 and since the resistance of |58 is much greater thanthat of network 85, the signal from network 50 will be negligible andwill not affect the control network.

If it is necessary for the pilot to take over control in an emergencyfrom the flight engineer, it is desirable that the system provide formaximum power. Under these circumstances, the switch 95 isV moved fromthe position shown on the drawing into the maximum power position wherethe respective switch arms 96, 91, and 98 engage contacts 99, |I, and|03. One effect of moving the switch into the maximum power position isto shift the control point of the electrical network 5.0 from the slider55 to the right end of the resistor 54. Since the slider 55 was normallyconnected to` ground by way of conductor 58, contact |00-, and switcharm 95, it is but necessary to shift the ground position of the resistor54 to another position by any means to establish a new control point forthe electrical network. Since the maximum power output is desired fromthe electrical network it is necessary to ground that portion of theresistor 54 which will give a control signal to the amplier 40 whichwill cause the waste gate motor 3|- to reposition itself to give ahigher input pressure to the engine. This so occurs when the right endof resistor 54 is grounded by way of conductor |85, switch contact 99,and switch arm 96. It will be noted that the former grounding circuitfor the slider 55 has now been opened with the movement of contact arm96 from engagement with switch contact |00 to engagement with switchcontact 99.

Water injection to the system is established by the movement of switcharm 91 into engagement with contact |0| and the movement of switch arm98 into engagement with contact |03. The water control relay |30 willnow be energized through a new circuit and this may be traced from thepositive terminal of the battery |06 through conductors |60, 6|, Switcharm 01, switch contact IDI, conductor |64, switch arm 98, switch contact|03, conductor |86, conductor |69, relay winding |3| to ground |68 andthus to ground |95 at battery |06. As mentioned before, the energizingof the relay winding |3| moves the switch arm |33 into engagement withswitch contact |34 to close the energizing circuit for the electricallyoperated water valve I4! which injects water into the input system ofthe engine.

As mentioned before, the wiper H4 associated with pressure selectingslider 55 engages either contact surfaces ||5 or H6 depending upon theposition of the slider arm 55. When this slider arm is in the low rangeof positions (0 to 5) the wiper ||4 engages contact surface H5 and whenthe pilot emergency switch 95 is in the position shown on the drawingthe previously traced energizing circuit for the control positionresponsive relay I8 will be completed. When the relay I8 is energized itmoves the switch arm |22 into engagement with contact |20 and out ofengagement with contact I2I. With the switch arm |22 in engagement withswitch contact |20, it is impossible to establish a circuit to theauxiliary control network 85 as long as these contacts remain closed.This is to prevent the auxiliary control network from being connectedinto the main electrical network when the slider 55 is positioned in thelow range from 0 to 5 on resistor 54. As pointed out above, the circuitfor this control position responsive relay ||8 is completed when switcharm 91 engages switch contact |02 of the pilots emergency switch 95.However, when this switch is moved to the maximum power position theswitch arm 91 moves into engagement with switch contact |0| andtherefore breaks the energizing circuit to relay ||8. The switch arm |22oi relay IIB then moves back into engagement with switch contact |2| tomake it possible to complete an electrical circuit to the auxiliarycontrol network should a further switching sequence occur.

Assuming again that the pilot has moved the emergency switch 95 in themaximum power position and the water control relay |30 is energized, thewater valve relay lili will also be energized as above explained andwith the presence of water the relay |50 will be energized by the actionof the bellows |56 closing contacts |41 and |48 to in turn move theswitch arm |53 into engagement with switch contact |55. Should the waterassembly fail for any reason, the switch contacts |41 and 58 will opendue to the retraction of the bellows |45 and the relay |50 will bedeenergized moving the switch arm |53 back into engagement with switchcontact |54. With switch arm |53 engaging switch contact |55. theauxiliary control network 65 will be switched back into the circuit andthis circuit may be traced from the slider 55 of the pressure responsivenetwork 60 through conductor |11, switch arm |53, switch contact |54,conductors |19 and |80, switch contact |23y switch arm |21, conductor 8|switch arm |22, switch contact |2|, conductor |82, to slider 9010i theelectrical network 85. Here again, the electrical control point of theelectrical network will be switched back to a maximum dry power positionto prevent excessive pressures from being developed in the engine tocause damage thereto, Y

By switching the pilots emergency switch 95 back into the position shownon the drawing, the electrical network control point will be shiftedback to the slider- 55 and the pressure then maintained at the input ofthe engine will be according to the pressure setting established by theposition of the slider 55.

A deicing function may be accomplished by the present apparatus byswitching the flight engineers carburetor heat switch |25 from theposition shown so that the switch arms |26 and |21 do not engage theirrespective contacts |29 and |28. Also, the throttle arm must be in theretarded position so that the switch contact ||2 does not engage thesurface ||3. While deicing, it is also necessary to have the pilotsemergency switch 95 in the position shown on the drawing. With theaforementioned switches in the positions referred to, it will be obviousthat the slider 55 may be moved through the entire range of from 0 to l0without instigating water injection. This may readily be seen when theslider 55 is in the range of from 5 to 10 on the resistor 54, when thereis normally water injection, the blade ||4 will be engaging contactsurface H5. It will be remembered that the circuit that was normallyenergizing the water control relay |30 was completed from the positiveterminal of the battery |65 through conductor |68, conductor IGI, switcharm switch contact |02, conductor |52, blade ile, switch contact H6,conductor |63, switch il Y contact '104,'switchf arm 93conductor 164,cond uctor 155switch Contact |29, switch arm |26, conductor 155,conductor |51, and relay winding `13|to ground 159. With the opening ofthe carburetor heat switch 125, the water control relay energizingcircuit will be broken and the relay `vwill not be energized as long asthe carburetor VVtween 0 and 5 Von the resistor 50 so that the controlposition responsive relay l 18 is energized and its switch arm 122is inengagement with switch contact 120. The circuit to relay winding 119 isagain traced from the positive terminal of theV battery |06 throughv160, conductor 15|, switch bladev 91, switch contact |02, conductor |62,blade 1M, switch contact 15, conductor |81, and relay winding 19 toground |88. When the switch arm '|22 engages switch contact 120, it isnot possible to establish an electrical connection to the network 85since the switch arm 122 is no longer in engagement Vwith contact 121.Advancing the throttle I 1 while theslider 55 is in the low range, willhave V`no switching effect upon the electrical network'. Howevenuas soonas the slider 55 is moved into the range of from 5 to 10 on the resistor54 the relay IIB will be deenergized and the switch arm 122 will moveinto engagement with Aswitch contact 121. Now, with the movement of thethrottle |11 into the advanced position so that the switch contactengages the contacting surface 1 i3 a circuit will be completed to theVmaximum "dry power network or auxiliary network 05.- This circuit may betraced from the slider 65 of i the pressure control network 60 throughthe conductor 111, switch arm |53, contact 154 (since there'is no waterpresent in the system and relay |50 is deenergized), conductor119,"conductor 190, throttle arm 111, switch contact 1|2,contacting'surface |13, conductor |91, switch arm 122, switch contact|21, conductor 182, to slider 90 of the auxiliary control network 85. Asin previous cases,rthe connection of network 85'into the circuit to theamplifier limits the value of the pressure which can be maintained. wTheV throttle switching assembly |10, therefore, isl effective toprevent excess pressures being built up in the carburetor during thedeicing Aoperation frombeing allowed to pass to the engine proper andcause damage thereto.

In the event that during the deicing operation by the flight engineer,the pilot should desire maximum power output from the engine with waterinjection, the closing of the pilots energizing switch 95 into themaximum power output position would by-pass the carburetor heat switchwhich was formerly maintaining the water control relay 130 deenergized.This circuitis again traced from the positive terminal of battery 105through conductors 1150 and 15|, switch arm 91, contact |01, conductor1M, switch arm 98, contact |03, conductor |85, conductor 161, relaywinding |31 to ground |58. When water control relay |30 becomesenergized the switch .arm |33 again moves into engagement with rswitchcontact 13e to thereby energize the watercontrol Valve |41 and the waterresponsive relay |50 when the contacts |41 and 148 have been closed bythe expansion of the bellows., |,4.5-.

With the carburetor heat switch in the open position and the maximumpowerswitch actuated, should there be a water Yfailure the electricalnetwork will be again switched back to the maximum vdry power controlnetwork 85 by way of the throttle position responsive switches. Thiscircuit may be traced Vfrom the slider 65 of the pressure responsivenetwork 50 through the conductor 111, switch arm |53, switch contact15d, conductors |19 and |99, throttle arm 1 1'1 switch contact |12,conducting Surface |13, conductor 19|, switch contactl 12|, switch arm|22, conductor 192, to slider 99 of the auxiliary control network 35.With the throttle assembly |15 Vin the retardedposition so that theswitch contact 1|2 was not engaging the surface i3, there wouldbe nodanger resulting from excess engine pressures for the excessive pressurebuilt up because the control network was in the maximum position wouldbe retained within the carburetor and would not be allowed to pass intethe engine because of the fact that the throttle was in the retardedposition.

If for any reason it is necessary to feather one of the propellers on amultiple engine installation, the propeller feathering control whenactuated causes the propeller to be driven to the f-ull featheredposition by means not shown on the drawing. Associated with thefeathering control is switch arm and contact |31 which open the watervalve energizing circuits whenever a propeller is feathered. With thepropeller feathered, the engine will be stopped so obviously waterinjection would not be wanted here.

From the foregoing it will be noted that an anti-detonant injectioncontrol apparatus has been provided which has provisions for deicing ofthe carburetor of a supercharged engine with pressures normally inexcess of those injected into the engine proper withoutantidetonantinjection, and to provide therewith throttle switching meansfor establishing a maximum dry power position in the event the throttleis advanced when the carburetor is being deiced by pressures in excessof those desired at the engine without antidetonant injection.

It may further be seen that a control apparatus has been provided whichmay be controlled from a remote point to establish a maximum pressurecondition on emergency at the intake of a supercharged engine and tofurther inject antidetonant into that intake system independently of thecontrol settings made elsewhere in the control apparatus. i

While we have disclosed our control apparatus in connection with anairplane engine and while it is particularly suitable for such anapplication there, it is to be understood that it could be employed inany pressure controlled engine. In generaLrwhile we have disclosed thespecific embodiment of our invention, it is to be understood that thisisfor purposes of illustration and that our invention is to be limitedsolely by the scope of the appended claims. Y Y

We claim:

l. In control `apparatus for controlling Vthe pressure of the airdelivered tothe intake manifold of an engine having means `for injectingan antidetonant into the engine, the combination comprising, regulatingmeans for controlling the pressure of the air, manual means for`variably selecting the pressure to be maintained by saidl regulatingmeans, throttle position responsive means, carburetor heat control meansoperable to effect heating in the carburetor of Van engine.'

auxiliary means for selecting a xed pressure to be maintained, and meansoperable to render effective said auxiliary means and ineffective saidmanual means when said manual means is posi` tioned in one range ofvalues and said throttle position responsive means is in one range orsaid carburetor heat control means is not operative.

2. In a control apparatus for controlling the pressure and antidetonantcontent of air delivered to the intake manifold of an engine, thecombination comprising, a complex electrical network for regulating thepressure of air delivered to an engine, said network including controlmeans, pressure responsive means, and balw ancing means, antidetonantcontrol means, means responsive to the position of the control means ofsaid network, means energizing said antidetonant control means when saidlast named means is in one range of Values, auxiliary control means,antidetonant responsive means, means connecting said auxiliary controlmeans in said network when said antidetonant responsive means does notdetect antidetonant, and means operable to energize said antidetonantcontrol means independently of the last named energizing means.

3. In a control apparatus for controlling the pressure and antidetonantcontent of air delivered to the intake manifold of an engine, thecombination comprising, regulating means for controlling the pressure ofthe air, manual means for variably selecting the pressure to bemaintained by said regulating means, control means for affectinginjection of antidetonant into the engine, means responsive to theposition of sai-d manual means, means including said responsive meansactuating said control means when said manual means is in one range ofvalues, safety means operative only on the presence of antidetonant,means connecting said safety control in the actuating circuit of saidcontrol means, auxiliary means for selecting a fixed pressure to bemaintained, and further means including said responsive means forrendering said auxiliary means eifective and said manual meansineffective when said control means is rendered inoperative by saidsafety means.

4. In a control apparatus for controlling the pressure and antidetonantcontent of air delivered to the intake manifold of an engine, thecombination comprising, regulating means for controlling the pressure ofthe air, manual means for variably selecting the pressure to bemaintained by said regulating means, throttle position responsive means,carburetor heat control means, antidetonant control means, antidetonantresponsive means, means responsive to the position of said manual meansfor actuating said antidetonant control means through said antidetonantresponsive means, auxiliary means for selecting a predeterminedpressure, and means oonnecting said auxiliary means to be eifective andsaid manual means ineffective when either said throttle positionresponsive means or said carburetor heat control means is actuated andsaid antidetonant responsive means is inoperative.

5. In a control apparatus for controlling the pressure and antidetonantcontent of air deliverered to the intake manifold of an engine, thecombination comprising, regulating means for controlling the pressure ofthe air, manual means for variable selecting the pressure to bemaintained by said regulating means, emergency pressure control meansoperable when actuated to establish a predetermined pressure,antidetonant control means, means responsive to the position of saidmanual means, means including said position responsive means foractuating said antidetonant control means when said manual means is inone range of values, and means including said emergency pressure meansfor energizing said antidetonant control means regardless of theposition of said manual means.

6. In a control apparatus for controlling the pressure and antidetonantcontent of air delivered to the intake manifold of an engine, thecombination comprising, a complex electrical network, said networkincluding control means, pressure responsive means, and balancing means,carburetor heat switch means, throttle position responsive means,antidetonant control means, means responsive to the position of thecontrol means of said network, means normally energizing saidantidetonant control means when the control means of said network is inone range of values, means for deenergizing said anti-detonant controlmeans including said carburetor heat switch means, auxiliary controlmeans, and means connecting said auxiliary control means in said networkwhen said carburetor heat switch means is deenergizing said antidetonantcontrol means and said throttle responsive means is actuated.

7. In a control apparatus for controlling the pressure and antidetonantcontent of air delivered to the intake manifold of an engine, thecombination comprising, a complex electrical network, said networkincluding control means, pressure responsive means, and balancing means,carburetor heat switch means, throttle position responsive means,antidetonant control means, means responsive to the position of thecontrol means of said network, means normally energizing saidantidetonant control means when the control means of said network is inone range of Values, means for deenergizing said antidetonant controlmeans including said carburetor heat switch means, auxiliary controlmeans, means connecting said auxiliary control means in said networkwhen said carburetor heat switch means is deenergizing said antidetonantcontrol means and said throttle responsive means is actuated, andfurther means for disconnecting said auxiliary control means from saidnetwork and energizing said antidetonant control means independently ofsaid carburetor heat switch means.

8. In a control apparatus for controlling the pressure and antidetonantcontent of air delivered to the intake manifold of an engine, thecombination comprising, regulating means for controlling the pressure ofthe air, manual means for variably selecting the pressure to bemaintained by said regulating means, emergency pressure control meansoperable when actuated to establish a predetermined pressure,antidetonant control means, means responsive to the position of saidmanual means, means including said position responsive means foractuating said antidetonant control means when said manual means is inone range of values, auxiliary pressure control means, antidetonantresponsive means, means including said emergency pressure control meansfor energizing said antidetonant control means regardless of theposition of said manual means, and further means including saidantidetonant responsive means for rendering only said auxiliary pressurecontrol means eiective to Control the pressure maintained by saidregulating means when said antidetonant control is rendered inoperativeby said antidetonant responvsive means.

9. In a control apparatus for controlling the pressure and antidetonantcontent of air deiivered to the intake manifold of an engine, theAcombination comprising, control means including a slider normallyconnected to ground for variably adjusting the controlling effect o saidmeans, pressure responsive means, balancing means, means connecting saidcontrol means, said pressure responsive means and said balancing meansin a complex electrical network, the output of which is between apointon said balancing means and ground, regulating means connected tothe output of said network to regulate the air pressure to the engine,switch means responsive to the position o the slider of said controlmeans, antidetonant control means, means energizing said antidetonantcontrol means including said switch means when the slider of saidcontrol means is in one range of values, and auxiliary switch meansoperable to energize said antidetonant control means independently ofsaid responsive switch means.

l0. In a control apparatus according to claim 9 wherein said auxiliaryswitch means renders inoperative the slider of said control means andconnects one portion of said control means to ground to call for amaximum pressure at said regulating means.

11. In a control apparatus for controlling the pressure and antidetonantcontent of air delivered to the intake manifold of an engine, thecombination comprising, control means including a slider normallyconnected to ground for variably adjusting the controlling effect ofsaid means, pressure responsive means, balancing means, means connectingsaid control means, said pressure responsive means and said balancingmeans in a complex electrical network, the output or" which is between apoint on said balancing means and ground, regulating means connected tothe output of said network to regulate the air pressure to the engine,switch means responsive to the position of the slider of said controlmeans, antidetonant control means, means energizing said'antidetonantcontrol means including said switch means when the slider of saidcontrol means is in one range of values, and carburetor heat switchmeans operable to deenergize said antidetonant control means whenenergized by said responsive switch means, said carburetor switch meanspermitting full movement of the slider of said control means withoutenergizing said antidetonant control means.

l2. In a control apparatus for controlling the pressure and antidetonantcontent of air delivered to the intake manifold of an engine, thecombination comprising, control means including a slider normallyconnected to ground for variably adjusting the controlling eiect of saidmeans, pressure responsive means, balancing means, means connecting saidcontrol means, said pressure responsive means and said balancing meansin a complex electrical network, the output of which is between a pointon said balancing means l and ground, regulating means connected to theoutput of said network to regulate the air pressure to the engine,switch means responsive to the position of the slider of said controlmeans, antidetonant control means, means energizing said antidetonantcontrol means including said switch means .when the slider of saidcontrol means is in one range of values, auxiliary con- 'trol means,throttle switch means, carburetor pressure responsive means, balancingmeans,

means connecting said control means, said pressure responsive means andsaid balancing means in a complex electrical network, the output ofwhich is between a point on said balancing means and ground, regulatingmeans connected to the output of said network to regulate the airpressure to the engine, switch means responsive to the position of theslider of said control means, antidetonant control means, meansenergizing said antidetonant control means including said switch meanswhen the slider of said control means is in one range of values,auxiliary switch means, means including said auxiliary switch means forenergizing said antidetonant control means and reconnecting said networkto call for a maximum pressure at said regulating means, antidetonantresponsive means, auxiliary control means, means including saidantidetonant responsive means for connecting said auxiliary controlmeans in said network when said antidetonant responsive means fails tooperate.

14. In control apparatus for controlling the pressure and antidetonantcontent of air delivered to the intake manifold of an aircraft engine,the combination comprising, means for controlling the pressure of theair, a manual selector adapted to be located at one point in an aircraftfor adjusting said pressure controlling means to select the pressuremaintained thereby, antidetonant control means for causing antidetonantto'be supplied to said engine, means normally operative upon said manualselector being moved to a high range to cause said antidetonant controlmeans to assume an antidetonant supplying condition, means forselectively rendering said last named means ineffective whenhighpressures are desired without the injection of an antidetonant, andmeans including a controller adapted to be located at a remote pointfrom said manual selector and ei'ective upon actuation thereof to causesaid pressure controlling means and said antidetonant control means toassume conditions causing a high pressure and injection of theantidetonant to be maintained regardless of the positions of said manualselector or of said previously named means.

15. In a condition control apparatus, the combination comprising, acomplex balanceable electrical network, said network having a pair ofoutput terminals and a manually adjusted member normally connected toone of said terminals to adjust the balance of said network, conditioncontrolling means connected to and affected by said network formaintaining a condition within predetermined limits in accordance withthe balance of said network condition responsive means connected incontrolling relation to said network and adapted to effect operation ofsaid controlling means upon the controlled condition assuming a valueindicative of the need for a change in the condition, and manuallyoperated switch means vconnected to one of said output terminals, saidswitch means being operative when actuated to shift said one outputterminal to another position in said network where a predeterminedunbalance will exist on said network which is independent of theposition of said member and which is such as to call for a maximum ofthe controlled condition.

16. In a condition control apparatus, the combination comprising, acomplex balanceable electrical network, said network having a pair ofoutput terminals and a manually adjusted member normally connected toone of said terminals to adjust the balance of said network, conditioncontrolling means connected to and aected by said network formaintaining a condition within predetermined limits in accordance withthe balance of said network condition responsive means connected incontrolling relation to said network and adapted to effect operation ofsaid controlling means upon the controlled condition assuming a valueindicative of the need for a change in the condition, switch meansconnected to one of said output terminals, said switch means beingoperative when actuated to shift said one output terminal to anotherpoint in said network where a predetermined unbalance will exist on saidnetwork, and second switch means connected to said network forestablishing a further unbalance of said network which will call for avalue of the controlled condition which is less than that called for bythe operation of said rst switch means, said second switch means beingoperated upon said condition going beyond a maximum safe value.

17. In a condition control apparatus, the combination comprising, acomplex balanceable electrical network, said network having a pair ofoutput terminals and a manually adjusted member normally connected toone of said terminals '18 to adjust the balance of said network,condition controlling means connected to and aiected by said network formaintaining a condition within predetermined limits in accordance withthe balance of said network condition responsive means connected incontrolling relation to said network and adapted to effect operation ofsaid controlling means upon the controlled condition assuming a valueindicative of the need for a change in the condition, switch meansconnected to one of said output terminals, said switch means beingoperative when actuated to shift said one output terminal to anotherpoint in said network where a predetermined unbalance will exist on saidnetwork, and second switch means connected to said network forestablishing a further unbalance of said network which will call for avalue of the controlled condition which is less than that called for bythe operation of said rst switch means, said second switch means beingoperated upon said condition going beyond a maximum safe value, said rstswitch means being eiTective regardless of the position of said manuallyadjusted member and said second switch means being effective only whensaid manually adjusted member is within a predetermined range and saidfirst switch means is not operative.

HUBERT T. SPARROW. ALEX B. CHUDYK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,392,565 Anderson et al Jan. 8,1946 2,431,590 Smith Nov. 25, 1947

